HDD Crossing Across River Vatrak for Palanpur Vadodara Pipeline Project of 18”+6” x 1400 Meters of Hindustan Petroleum Corporation Limited
The Vatrak is a tributary of the Sabarmati River which flows for 243 kilometers in Gujarat, India. This river is lifeline to millions of Indians along it’s course. The maximum width of the river is 900m.
This job was a part of Pipeline “Palanpur Baroda Pipeline Project Part B” , Owner: Hindustan Petroleum Corporation Limited , Engineering Consultants: Engineers India Limited and Contractor : Ace Engery Infrastructure Pvt. Ltd, Mumbai carrying Gas.
The River’s width was 800 m, where the owner’s designed it to be crossed. Next level Project Private Limited had designed the crossing for the length of 1450m keeping enough of margin on the either side of the bank for the river to change it’s course and meandering in future.
Key Technical Specifications
- Length : 1440 M
- Diameter of Pipe : 18 Inches + 6 Inches
- Depth : 15 M below the Bed Level
- Strata : Gravel and Silty Clay.
Next Level Projects Private Limited did a detailed planning for the job. As this crossing has it’s own set of challenges in terms of Drilling Strata, Timeline and Right of way.
We had to design the project in such a way that the Footprint of the Site Set-up had to minimum and the time frame was to complete the job before the monsoon season starts.
We selected Custom Built HDD Rig, a 320 Ton Rig with National Oilwell Mud Pump.
We used Paratrack-II system for Guidance. We drilled with 6-7/8 Mud Motor with 9-7/8 TCI Drilling Bit. To provide the stability to Drill Pipe we Pushed Washover Casing of 12.75 Inches upto the length of 120 Meters from the Rig Side. The Casing helps in providing the stability to Downhole Tools and helps in getting better Mud Returns.
We planned to do Two Stage Reaming. First Reaming Pass was of 20 Inches and Second Reaming Pass was of 30 Inches. Taking Step Cuts in HDD is the norm. It helps in Stabilising the hole and keep the Torque values low.
While Reaming we had to change the Mud Chemistry as we found that Gravels and Clay is packing on the reamer. We added Surfactants and weighing agent to our Mud. This enabled us with better flow of cuttings out of the hole and better penetration rate.
Pipe string of 18” was assembled in one single string, on rollers. As points where there were two road crossings, the pipe was elevated onto the rollers and iron plate of 25mm was placed on the ramp over the pipe to give easy access to villagers. Manning the 1450 meter section, NLP used 2 hydra, 3 backoe and 2 side booms to ensure smooth flow of pipe into the ground.